Hot gas path component and methods of manufacture

ABSTRACT

Various embodiments of the disclosure include a turbomachine component. and methods of forming such a component. Some embodiments include a turbomachine component including: a first portion including at least one of a stainless steel or an alloy steel; and a second portion joined with the first portion, the second portion including a nickel alloy including an arced cooling feature extending therethrough, the second portion having a thermal expansion coefficient substantially similar to a thermal expansion coefficient of the first portion, wherein the arced cooling feature is located within the second portion to direct a portion of a coolant to a leakage area of the turbomachine component.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional application of co-pending U.S. patentapplication Ser. No. 14/584,442, filed Dec. 29, 2014, which is herebyincorporated by reference in its entirety.

GOVERNMENT LICENSE RIGHTS

This invention was made with Government support under contract numberDE-FC26-05NT42643, awarded by the Department of Energy. The governmenthas certain rights in the invention.

FIELD OF THE INVENTION

The subject matter disclosed herein relates to gas turbomachines. Moreparticularly, the subject matter disclosed herein relates to componentsin gas turbomachines, and methods of manufacturing such components.

BACKGROUND OF THE INVENTION

Gas turbomachine components are designed to withstand significanttemperatures in order to achieve a desired lifespan. Some of thisheat-enduring capability is accounted for in material type, and some isaccounted for in the incorporation and design of cooling features in thecomponents. However, as material prices increase, and the ability tomanipulate those materials becomes more challenging, the cost ofproducing a gas turbomachine component with desired lifespan isincreasingly difficult.

BRIEF DESCRIPTION OF THE INVENTION

Various embodiments of the disclosure include a turbomachine component.and methods of forming such a component. Some embodiments include aturbomachine component including: a first portion formed of at least oneof a stainless steel or an alloy steel; and a second portion bonded tothe first portion, the second portion formed of a nickel alloy includingan arced cooling feature extending therethrough, the second portionhaving a thermal expansion coefficient substantially similar to athermal expansion coefficient of the first portion, wherein the arcedcooling feature is located within the second portion to direct a portionof a coolant to a leakage area of the turbomachine component.

A first aspect of the invention includes a turbomachine componentincluding: a first portion formed of at least one of a stainless steelor an alloy steel; and a second portion bonded to the first portion, thesecond portion formed of a nickel alloy including an arced coolingfeature extending therethrough, the second portion having a thermalexpansion coefficient substantially similar to a thermal expansioncoefficient of the first portion, wherein the arced cooling feature islocated within the second portion to direct a portion of a coolant to aleakage area of the turbomachine component.

A second aspect of the invention includes a method including: forging orcasting a first portion of a turbomachine component; additivelymanufacturing a second portion of the turbomachine component, theadditively manufacturing of the second portion of the turbomachinecomponent including forming an arced cooling feature within the secondportion, the second portion formed of a material having a thermalexpansion coefficient substantially similar to a thermal expansioncoefficient of the first portion, wherein the arced cooling feature islocated within the second portion to direct a portion of a coolant to aleakage area of the turbomachine component; and bonding the secondportion to the first portion.

A third aspect of the invention includes a method including: additivelymanufacturing a section of a turbomachine component, the additivelymanufacturing of the section of the turbomachine component includingforming an arced cooling feature within the section, wherein the arcedcooling feature is located within the section to direct a portion of acoolant to a leakage area of the turbomachine component; and bonding thesection of the turbomachine component to a preformed base section of theturbomachine component, wherein a thermal expansion coefficient of thesection of the turbomachine component and a thermal expansioncoefficient of the preformed base section are substantially similar.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a disjointed three-dimensional perspective view of aturbomachine component according to various embodiments of thedisclosure.

FIG. 2 shows a partially transparent three-dimensional perspective viewof the turbomachine component of FIG. 1, according to variousembodiments of the disclosure.

FIG. 3 shows a three-dimensional perspective view of a portion of theturbomachine component of FIGS. 1-2 according to various embodiments ofthe disclosure.

FIG. 4 shows a close-up three-dimensional perspective view of a portionof the turbomachine component of FIGS. 1-3 according to variousembodiments of the disclosure.

FIG. 5 shows a second close-up three-dimensional perspective view of aportion of the turbomachine component of FIGS. 1-3 according to variousembodiments of the disclosure.

FIG. 6 shows a three-dimensional perspective view of a set ofturbomachine buckets according to various embodiments of the disclosure.

FIG. 7 shows a flow chart depicting processes according to variousembodiments of the disclosure.

FIG. 8 shows a block diagram of an additive manufacturing processincluding a non-transitory computer readable storage medium storing coderepresentative of an turbomachine component according to variousembodiments of the disclosure.

It is noted that the drawings of the invention are not necessarily toscale. The drawings are intended to depict only typical aspects of theinvention, and therefore should not be considered as limiting the scopeof the invention. In the drawings, like numbering represents likeelements between the drawings.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, the subject matter disclosed herein relates to gasturbomachines. More particularly, the subject matter disclosed hereinrelates to components in gas turbomachines, and methods of manufacturingsuch components.

In contrast to conventional approaches, various aspects of disclosureinclude approaches for forming a cooling feature in a (gas) turbomachinecomponent, e.g., in a hot-gas-path (HGP) component, and the turbomachinecomponent formed including such a component. Various particular aspectsinclude forming a portion of the turbomachine component by conventionalforging or casting, and using additive manufacturing to form theremainder (second portion) of the turbomachine component, where thesecond portion includes the cooling feature. The process can furtherinclude bonding the first portion with the second portion after formingthe cooling feature.

In various embodiments, the cooling feature can include a gradual, orarced pathway, which allows coolant to flow through the component,effectively transferring heat away from the component. In variousembodiments, the first portion of the component and the second portionof the component are formed of the same material. However, in variousembodiments, the second portion is formed of a different material thanthe first portion, but has a thermal expansion coefficient that isapproximately the same (or similar) as that of the material of the firstportion. For example, the thermal expansion coefficient may vary byapproximately 5-25 percent. It is understood that according to variousother embodiments, an additional cooling management configuration couldbe utilized to reduce the impact of any difference in thermal expansioncoefficient between the material of the first portion and the materialof the second portion. These other embodiments may allow for adifference in thermal expansion coefficient between the material of thefirst portion and the material of the second portion of greater than 10percent.

In some cases, the first portion can be formed of a stainless steel oran alloy (e.g., HR-120 alloy, available from Haynes International,Kokomo, Ind.). In various embodiments, the second portion can be formedof a nickel alloy (e.g., IN-625 or IN-617, both available from theSpecial Metals Corporation, New Hartford, N.Y.; or H-230, H-282 or HXalloy, each also available from Haynes International).

In various embodiments, the turbomachine component can include a shroudof a turbomachine (e.g., gas turbomachine) blade (or bucket). As isknown in the art, the shroud is located at the radially outer portion ofthe blade, and guards the tip of the blade as it rotates within theturbomachine. In various embodiments, the turbomachine component caninclude a shroud on a first stage blade (stage one shroud (S1S)), or ashroud on a second stage blade (stage two shroud (S2S)).

In the following description, reference is made to the accompanyingdrawings that form a part thereof, and in which is shown by way ofillustration specific example embodiments in which the present teachingsmay be practiced. These embodiments are described in sufficient detailto enable those skilled in the art to practice the present teachings andit is to be understood that other embodiments may be utilized and thatchanges may be made without departing from the scope of the presentteachings. The following description is, therefore, merely illustrativeof various aspects of the invention.

As used herein, the terms “axial” and/or “axially” refer to the relativeposition/direction of objects along axis A, which is substantiallyparallel with the axis of rotation of the turbomachine (in particular,the rotor section). As further used herein, the terms “radial” and/or“radially” refer to the relative position/direction of objects alongaxis (r), which is substantially perpendicular with axis A andintersects axis A at only one location. Additionally, the terms“circumferential” and/or “circumferentially” refer to the relativeposition/direction of objects along a circumference which surrounds axisA but does not intersect the axis A at any location.

FIG. 1 shows a three-dimensional perspective view of a sectionedturbomachine component 2, showing separation of two portions (sections)of the component for the purposes of illustration. FIG. 2 shows theturbomachine component 2 in a partially transparent three-dimensionalperspective view. As shown in FIG. 1 and FIG. 2, the turbomachinecomponent 2 (e.g., a gas turbomachine component, such as one in a hotgas path section of the gas turbomachine) can include a first portion 4formed of at least one of: a) stainless steel; or b) an alloy steel. Thefirst portion 4 can be formed according to various embodiments describedherein, for example, the first portion 4 can be forged or cast fromstainless steel or an alloy steel. The first portion 4 is joined to asecond portion 6 (shown separated in FIG. 1), for example, by a braze orweld joint 8. The second portion 6 is shown in greater detail in thethree-dimensional perspective views in FIGS. 3-5.

The second portion 6 can be formed of a nickel alloy or material withsimilar thermal expansion characteristics, and can be additivelymanufactured separately from the first portion 4. In variousembodiments, as described herein, the second portion 6 is formed using athree-dimensional printing process, or other additive manufacturingprocess allowing for formation of particular cooling features 10 (FIGS.3-5), described in further detail herein. The material forming thesection portion 6 can have a thermal expansion coefficient (or, heattransfer coefficient) substantially similar to the material used to formthe first portion 4. In various embodiments, the second portion 6 isformed of a distinct material than the first portion 4, which can helpto reduce the overall costs of the turbomachine component 2, as thesecond portion 6 may be formed of a less expensive material (e.g.,nickel alloy or similar thermally conductive material) that can bemanipulated by additive manufacturing. However, although the materialforming the second portion 6 may be a distinct material than thatforming the first portion 4, the two materials may have a substantiallysimilar thermal expansion coefficient, that is the second portion 6 mayhave thermal expansion coefficients that varies by less thanapproximately 25 percent from the thermal expansion coefficient of thefirst portion 4. As noted herein, according to various otherembodiments, an additional cooling management configuration could beutilized to reduce the impact of any difference in thermal expansioncoefficient between the material of the first portion and the materialof the second portion. These other embodiments may allow for adifference in thermal expansion coefficient between the material of thefirst portion and the material of the second portion of greater than 25percent.

Collectively, the first portion 4 and the second portion 6 can form aturbomachine bucket shroud (or simply, shroud) 12, illustrated in thethree-dimensional perspective view of FIG. 6. As described herein, theshroud 12 can be coupled with a turbomachine airfoil 14, viaconventional joining techniques (e.g., welding, brazing, etc.) to form aturbomachine bucket (or nozzle) 16 (several buckets/nozzles shown).Alternatively, a similar method may be used to form a portion of anozzle endwall(s), either as two separate portions (e.g., similarly tofirst portion 4 and second portion 6), or where the entirety of theendwall is formed as described with respect to the second portion 6.These endwall(s) could then be bonded to a turbomachine airfoil to forma complete turbomachine nozzle.

As shown in FIGS. 3-5, the second portion 6 can include a plurality ofcooling features 10, in particular, at least one arced cooling feature10A, for directing a portion of a coolant to a leakage area 18 of theturbomachine component 2 (shroud). The leakage area 18 is locatedproximate a joint between adjacent shrouds 12 in a set of turbomachineshrouds 12 (FIG. 6). That is, the leakage area 18 is distinct from thehot gas path (HGP) region 20, where the gas primarily impacts theairfoils 14 and affects mechanical motion of the blades as they rotateabout a rotor, as is known in the art. The leakage area 18 is locatedbetween adjacent bucket shrouds 12, as shown in FIG. 6.

Various conventional cooling paths direct a coolant into, the HGP region20, which result in inefficient usage of the coolant. In contrast,various cooling features 10, e.g., the arced cooling features 10A candirect coolant flow to the leakage area 18 between adjacent shrouds,such that coolant can be reused as leakage/cooling flow through theleakage flow path. Additionally, the arced shape of cooling features 10Aallows those features to enhance surface area contact with the shroud 12(when compared with straight-line cooling features), enhancing heattransfer from the shroud 12. Various additional cooling features 10 areshown in the bucket shroud 12 (e.g., in the second portion 6), whichform a winding path 22 through the second portion 6.

It is understood that according to various embodiments, the variouscooling features 10, and in particular, the arced cooling features 10A,can be formed by a series of angled, intersecting holes, or a series ofinterconnected plenums, which allow the flow of coolant to loop backover the leakage area 18. That is, the cooling features 10 may includefeatures which have a generally arched shape, but are not necessarilycomposed entirely of arcuate features.

As shown in FIG. 6, the buckets (nozzles) 16 can be inserted into slots24 in the rotor body 26, as is known in the art. The axis of rotation ofthe rotor body 26 is denoted as axis “a”, and the radial direction “r”is shown relative to that axis of rotation (a). As described herein, thearced cooling features 10A can include at least one outlet or inlet atthe circumferentially facing edge 28 of shroud 12, which faces asimilarly circumferentially facing edge 28 of an adjacent shroud 12.

As described herein, the turbomachine component 2 (e.g., gas turbineshroud 12) can be formed according to various processes, for example, intwo separate processes (one for each portion 4, 6), and subsequentlybonded together. This approach can allow for forming arced (coolingfeature 10A) or otherwise complex cooling features using additivemanufacturing (e.g., three-dimensional printing or layered depositiontechniques).

FIG. 7 shows a flow chart illustrating various processes in a methodaccording to embodiments. As shown, processes can include:

Process P0 (optional pre-process, depicted in phantom): forging orcasting a first portion 4 of a turbomachine component 2. As notedherein, this first portion 4 can be forged or cast from stainless steelor an alloy steel. In various embodiments, the first portion 4 may beformed prior to, or after, subsequently listed processes (e.g., formingsecond portion 6). In some cases, the first portion 4 can be forged orcast by a separate entity, e.g., a contracting entity, bulk producer,etc. and provided as a base for subsequent processes described herein.That is, in various embodiments, the first portion 4 may be obtainedwithout being forged or cast by the same entity that manufactures thesecond portion 6, or bonds the first portion 4 with the second portion 6to form the component 2;

Process P1: additively manufacturing the second portion 6 of theturbomachine component 2. As described herein, additively manufacturingthe second portion 6 can include three-dimensional printing and/orlayered deposition techniques, and the source material for the secondportion 6 can include a nickel alloy. In any case, the thermal expansioncoefficient of the source material for the second portion 6 can besubstantially similar (+/−25%) of the thermal expansion coefficient forthe first portion 4, to prevent undesirable differential thermalexpansion during operation, e.g., in gas turbomachine). In additivelymanufacturing the second portion 6, an arced cooling feature 10A (alongwith other cooling features 10) is formed, where the arced coolingfeature 10A is sized and located to direct a portion of a coolant (e.g.,liquid coolant such as water) to a leakage area 18 of the component 2.Process P2, in the case that the additive manufacturing includesthree-dimensional printing, can be performed, e.g., by at least onecomputing device controlling a three-dimensional printer, as describedherein;

Process P2: joining the second portion 6 to the first portion 4. Thisprocess can include brazing or welding the two portions 4, 6 together,using conventional brazing/welding techniques. Process P2 may beperformed after the second portion 6 is fully formed, or, in someembodiments, depending upon the manufacturing approach (e.g., additivemanufacturing), while the second portion is in a nearly finalized state.Bonding the first portion 4 and the second portion 6 can form a completeshroud 12, as described herein; and

Process P3 (optional post-process, depicted in phantom): coupling theturbomachine component 2 (turbomachine shroud 12) to a turbomachineairfoil 14, to form a turbomachine bucket (or nozzle) 16. This processcan include welding or brazing the turbomachine component 2 to an end ofthe airfoil 14, according to conventional welding and/or brazingtechniques.

It is understood that in the flow diagrams shown and described herein,other processes may be performed while not being shown, and the order ofprocesses can be rearranged according to various embodiments.Additionally, intermediate processes may be performed between one ormore described processes. The flow of processes shown and describedherein is not to be construed as limiting of the various embodiments.

In any case, the technical effect of the various embodiments of thedisclosure, including, e.g., the 3D printing control system 114, is toadditively manufacturing a portion (e.g., second portion 6) of aturbomachine component 2.

The above-described turbomachine component 2 (e.g., second portion 6)can be manufactured using additive manufacturing. As used herein,additive manufacturing (AM) may include any process of producing anobject through the successive layering of material rather than theremoval of material, which is the case with conventional processes.Additive manufacturing can create complex geometries without the use ofany sort of tools, molds or fixtures, and with little or no wastematerial. Instead of machining components from solid billets of metal,much of which is cut away and discarded, the only material used inadditive manufacturing is what is required to shape the part. Additivemanufacturing processes may include but are not limited to: 3D printing,rapid prototyping (RP), direct digital manufacturing (DDM), selectivelaser melting (SLM) direct metal laser melting (DMLM), and/orelectron-beam (EB) melting. In some embodiments, DMLM has been found tobe advantageous.

To illustrate an example additive manufacturing process, FIG. 8 shows aschematic/block view of an illustrative computerized additivemanufacturing system 900 for generating an object 902. In this example,system 900 is arranged for DMLM. It is understood that the generalteachings of the disclosure are equally applicable to other forms ofadditive manufacturing. Object 902 is illustrated as a double walledturbine element; however, it is understood that the additivemanufacturing process can be readily adapted to manufacture turbomachinecomponent 2 (e.g., second portion 6). AM system 900 generally includes acomputerized additive manufacturing (AM) control system 904 and an AMprinter 906. AM system 900, as will be described, executes code 920 thatincludes a set of computer-executable instructions defining combustorcap to physically generate the object using AM printer 906. Each AMprocess may use different raw materials in the form of, for example,fine-grain powder, liquid (e.g., polymers), sheet, etc., a stock ofwhich may be held in a chamber 910 of AM printer 906. In the instantcase, turbomachine component 2 (e.g., second portion 6) may be made ofany conventional turbomachine component material such as nickel basedalloys, or other suitable materials for combustion system applications.As illustrated, an applicator 912 may create a thin layer of rawmaterial 914 spread out as the blank canvas from which each successiveslice of the final object will be created. In other cases, applicator912 may directly apply or print the next layer onto a previous layer asdefined by code 920, e.g., where the material is a polymer. In theexample shown, a laser or electron beam 916 fuses particles for eachslice, as defined by code 920. Various parts of AM printer 906 may moveto accommodate the addition of each new layer, e.g., a build platform918 may lower and/or chamber 910 and/or applicator 912 may rise aftereach layer.

AM control system 904 is shown implemented on computer 930 as computerprogram code. To this extent, computer 930 is shown including a memory932, a processor 934, an input/output (I/O) interface 936, and a bus938. Further, computer 932 is shown in communication with an externalI/O device/resource 940 and a storage system 942. In general, processor934 executes computer program code, such as AM control system 904, thatis stored in memory 932 and/or storage system 942 under instructionsfrom code 920 representative of turbomachine component 2 (e.g., secondportion 6), described herein. While executing computer program code,processor 934 can read and/or write data to/from memory 932, storagesystem 942, I/O device 940 and/or AM printer 906. Bus 938 provides acommunication link between each of the components in computer 930, andI/O device 940 can comprise any device that enables a user to interactwith computer 940 (e.g., keyboard, pointing device, display, etc.).Computer 930 is only representative of various possible combinations ofhardware and software. For example, processor 934 may comprise a singleprocessing unit, or be distributed across one or more processing unitsin one or more locations, e.g., on a client and server. Similarly,memory 932 and/or storage system 942 may reside at one or more physicallocations. Memory 932 and/or storage system 942 can comprise anycombination of various types of non-transitory computer readable storagemedium including magnetic media, optical media, random access memory(RAM), read only memory (ROM), etc. Computer 930 can comprise any typeof computing device such as a network server, a desktop computer, alaptop, a handheld device, a mobile phone, a pager, a personal dataassistant, etc.

Additive manufacturing processes begin with a non-transitory computerreadable storage medium (e.g., memory 932, storage system 942, etc.)storing code 920 representative of combustor cap 102. As noted, code 920includes a set of computer-executable instructions defining turbomachinecomponent 2 (e.g., second portion 6) that can be used to physicallygenerate the tip, upon execution of the code by system 900. For example,code 920 may include a precisely defined 3D model of turbomachinecomponent 2 (e.g., second portion 6) and can be generated from any of alarge variety of well known computer aided design (CAD) software systemssuch as AutoCAD®, TurboCAD®, DesignCAD 3D Max, etc. In this regard, code920 can take any now known or later developed file format. For example,code 920 may be in the Standard Tessellation Language (STL) which wascreated for stereolithography CAD programs of 3D Systems, or an additivemanufacturing file (AMF), which is an American Society of MechanicalEngineers (ASME) standard that is an extensible markup-language (XML)based format designed to allow any CAD software to describe the shapeand composition of any three-dimensional object to be fabricated on anyAM printer. Code 920 may be translated between different formats,converted into a set of data signals and transmitted, received as a setof data signals and converted to code, stored, etc., as necessary. Code920 may be an input to system 900 and may come from a part designer, anintellectual property (IP) provider, a design company, the operator orowner of system 900, or from other sources. In any event, AM controlsystem 904 executes code 920, dividing turbomachine component 2 (e.g.,second portion 6) into a series of thin slices that it assembles usingAM printer 906 in successive layers of liquid, powder, sheet or othermaterial. In the DMLM example, each layer is melted to the exactgeometry defined by code 920 and fused to the preceding layer.Subsequently, the turbomachine component 2 (e.g., second portion 6) maybe exposed to any variety of finishing processes, e.g., minor machining,sealing, polishing, etc.

When an element or layer is referred to as being “on”, “engaged to”,“connected to” or “coupled to” another element or layer, it may bedirectly on, engaged, connected or coupled to the other element orlayer, or intervening elements or layers may be present. In contrast,when an element is referred to as being “directly on,” “directly engagedto”, “directly connected to” or “directly coupled to” another element orlayer, there may be no intervening elements or layers present. Otherwords used to describe the relationship between elements should beinterpreted in a like fashion (e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” etc.). As used herein,the term “and/or” includes any and all combinations of one or more ofthe associated listed items.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

We claim:
 1. A method comprising: forging or casting a first portion ofa turbomachine component, the first portion including at least one of astainless steel or an alloy steel; additively manufacturing a secondportion of the turbomachine component, the second portion including anickel alloy, the additively manufacturing of the second portion of theturbomachine component including forming an arced cooling feature withinthe second portion, the arced cooling feature having an outlet, thesecond portion formed of a material having a thermal expansioncoefficient differing by 5 percent to 25 percent from a thermalexpansion coefficient of the first portion, wherein the second portionhas a leakage surface configured to be circumferentially facing andlocated in an axial-radial plane of a turbomachine, the leakage surfaceincluding the outlet, wherein the arced cooling feature is locatedwithin the second portion to direct a portion of a coolant to a leakagearea of the turbomachine component by way of the outlet, wherein thearced cooling feature loops back over itself in a radial direction in aplane perpendicular to the axial-radial plane; and joining the secondportion to the first portion.
 2. The method of claim 1, wherein theforging or casting of the first portion includes forging or casting fromat least one of a stainless steel or an alloy steel.
 3. The method ofclaim 1, wherein the additively manufacturing includesthree-dimensionally printing the second portion of the turbomachinecomponent.
 4. The method of claim 1, wherein the joining includeswelding or brazing the second portion to the first portion.
 5. Themethod of claim 1, wherein the first portion and the second portioncollectively form a gas turbine shroud after the joining.
 6. The methodof claim 5, further comprising joining the gas turbine shroud to aturbomachine airfoil.
 7. A method comprising: additively manufacturing asection of a turbomachine component using a base material including anickel alloy, the additively manufacturing of the section of theturbomachine component including forming an arced cooling feature withinthe section, the arced cooling feature having an outlet, wherein thearced cooling feature is located within the section to direct a portionof a coolant to a leakage area of the turbomachine component by way ofthe outlet, wherein the arced cooling feature loops back over itself ina radial direction in a plane perpendicular to the axial-radial plane,wherein the section of the turbomachine component has a leakage surfaceconfigured to be circumferentially facing and located in an axial-radialplane of a turbomachine, the leakage surface including the outlet; andjoining the section of the turbomachine component to a preformed basesection of the turbomachine component, wherein a thermal expansioncoefficient of the section of the turbomachine component differs by lessthan 25 percent from a thermal expansion coefficient of the preformedbase section.
 8. The method of claim 7, further comprising forging orcasting the preformed base portion from at least one of a stainlesssteel or an alloy steel prior to the additively manufacturing of thesection of the turbomachine component.
 9. The method of claim 7, whereinthe additively manufacturing includes three-dimensionally printing thesection of the turbomachine component.
 10. The method of claim 7,wherein the joining includes welding or brazing the section of theturbomachine component to the preformed base section of the turbomachinecomponent.
 11. The method of claim 7, wherein the joined section and thebase section collectively form a gas turbine shroud, the method furthercomprising bonding the gas turbine shroud to a turbomachine airfoil.